Fire alarm system



Feb. 21, 1939.

A. F. MARTEL 2,148,303

FIRE ALARM SYSTEM Filed Sept. 50, 1936 2 Sheets-Sheet l a L L-VQ-ZZ 34 4e i l W INVENTOR:

ADELARD F. MARTEL ATTORNEY.

Feb. 21, 1939. A MARTEL 2,148,303

FIRE ALARM SYSTEM Filed Sept. 50, 1936 2 Sheets-Sheet 2 --s2 so m g l l F :6. 4. M 53 42 a O 38 \x 1" INVENTOR:

ADE LARD F. MART El AT'i'ORNEY.

Patented Feb. 21, 1939 FIRE ALARM SYSTEM Adelard F. Martel, 'Burlingame, Calif., assignor, .by direct andrmesne assignments, of two-thirds to George W. one-third to -'cisco, Calif.

Gates, Burlingan1e,-Calif., and Arthur H. Eldredge, San

Fran- Appli'cation September 30,'1936,Seriai No. 103 260 3 Claims.

This invention relates to improvements in'fire alarm systems.

.Among the objects of :the invention is to provide automatic means at a central point for .5 indicating-the location of the blaze :for which the fire-alarm is given.

Another object is to utilize the existing individual telephone circuits in the fire alarm system thus enabling individual fire alarm indication by the addition of a common wire only.

Another object .is to disconnect the telephone circuit .from the fire alarm system so long as the telephone is in use.

vAnother object is to .render the fire location indicators operative until manually restored by the attendant.

:Another object is to sound a simultaneous alarm -at the fire stations affected so that the equipment is in readiness when the fire station is informed of the location of the 'fire from the central firealarm indicator board.

Another object is to permit simultaneous indication of aplurality'offiresshould occasion arise.

Anotherobjectisto provide a fire alarm switch capable of being operated automatically by a rise in temperature or manually.

Other objects and advantages will appear as this .description progresses.

In this specification and the accompanying drawings, the invention is disclosed in its preferred form. It is to be understood, however, that it is not limited to this form because it may. be embodied in other forms without departing from the spirit of the invention as defined by the claims following the description.

In the two sheets of drawings:

Fig.1isaschematicdiagram of the wiring of "a ifire alarm system constructed in accordance 'with this invention.

Fig. 2 is a horizontal section of the switch for giving the fire alarm.

Fig. 3 1's a vertical section of the same.

Fig. 4 is a detail view in side elevation of the itimeswitch'for discontinuing the sounding of the alarm at the fire stations.

In detail the construction illustrated in the drawings, referring more particularly to Fig. 1, comprises the telephone line wires l and 2. These wires areduplicated as shown at l and 2' for each of the telephone units in the system. The wires 1 and 1 are connected to the receiver 3, the transmitter 4, and the signal bell 5 in the manner conventional in thisart. The switch 6 :maintains the telephone circuit open so long CB5 asithen'eceiver-il is:on:the =hook 1. The wires 1 and 2 lead from the subscriber to the central exchange and terminate in the contacts *3 and '9 set in a jack in the usual switch board. Con- 'nectionis made between the individual telephone circuits by plugs such as it operated by an automatic dial system or by manual means.

'The tap wire ll leads from a line 2 and has the signal relay 5? and a battery it connected in series therein. The end of the wire 5 I is grounded at l4. The relay switch I5 is interposed in the wire H and is adapted to be opened when the coil 1'6 is energized.

The tap wire f! is-connected to the line I and leads to the ground l8 through the relay switch 19. The switch 1'9 is also opened when thecoil i6 is energized.

Raising the receiver 3 from the hook I closes the switch 6. Current then flows from the battery l3, through the signal coil l2, the wire H, the line 2, the closed switch 6 and over the line I. The circuit is completed through the wire 17, back to the battery i3 through the grounds l8 and M. The energized signal relay l2 places the automatic dial exchange apparatus in operative condition to receive the dial signals. In the case of manual exchanges, the relay I 2 operates an indicator designating the particular jack connected to the calling subscriber.

The relay coil l6 has one end grounded at 20. Its opposite end the contactor '22 adjacent the contact 9 in the jack. When the plug ii! is entered into the jack, the contactor 22 engages the contact 9. Current fiows from the central sourcenot showmto the line '2, through the contactor 22, the wire 2|, the coil 16, and back to the source through the ground at 20. Energizing the coil it opens the relay switches the operative telephone circuit from the preliminary signal system above described.

The apparatus thus far described 'ventional-central exchange telephone system well known to those skilled in the art. Reference may be had to standard textbooks for description of the detailed network. It is deemed sufficient to describe only the elements of that portion of the system to which the present invention is applied.

The apparatus provided by the present inven tion consists of the drop relays such as 23 which are individually connected by the wires 24 to the tap wires i! of each of the multiplicity-0f telephone circuits. The drop relays 23 are preferably located adjacent the telephone exchange boards so that the individual wires is the conis connected by the wire 2i to 24 can be rel- 1 i5 and I9 and disconnects atively short. When the telephone circuit is in use the opening of the relay switches l5 and H! by the relay coil l6 sequesters the fire alarm apparatus from the telephone circuit. The coils 23 are adapted to operate the index means 23.1: so that the exact address of the subscriber is shown when one of the coils is energized.

Each of the coils 23 is connected to the common line 25 which has the relay coil 26 and the battery 21 interposed therein. The coil 26 is adapted to close the switch 28 which is connected to the battery 29 by the wire 38. The opposite side of the switch is connected by the wire 3! to the audible and visual signals 32 and 33 in proximity to the drop relays 23. The wire 34 completes the circuit from the signals 32, 33 back to the battery 29.

Fire alarm signals in the fire houses 35-35 are connected to the switch 28 by the wire 36. The circuit is completed back to the battery 29 by the wire 31.

The motor 38 is also connected to the switch 28 and the battery 29 by the wires 39 and 49 respectively. The motor 38 is the actuating element of a time switch. It comprises the insulating disk 4! driven at predetermined speed by the motor 38. The bus contact 42 is fixed on the disk 4| and is adapted to close the contacts 43 and 44 at the end of a cycle of movement of the time switch.

The contacts 43 and 44 are interposed in a circuit comprising the wire 45, the relay coil 46, the wire 41, the battery 29, the switch 28, and the wire 48. The relay coil 46 controlled by the contacts 43, 44 is adapted to open the switch 28.

The common line 25 extends to the address of each of the subscribers of the given central exchange. It is connected to each of the individual telephone lines 2 by the wires 48. The fire alarm switches 49 are mounted at points convenient to the subscriber and interposed in the wires 23. The switches 49 are preferably protected by breakable glassnot shown-to prevent their mischievous operation. If desired, the switches may be multiplied and connected in parallel in the line 48 as at 49a: so that they may be mounted at a number of strategic points.

The construction of the switch 24 is illustrated in Figs. 2 and 3. It consists of the base 59 of porcelain or similar insulating material having the lever 5| centrally pivoted therein. The lever extends through the slot 52 in the base and terminates in the hook 53. The spring 54 urges the lever 5| toward the operative position. The end 56 of the slot limits the operative travel of the lever ii. The lever is arranged so that it moves into and out of engagement with the contact 51 in its travel toward the stop 58.

The lever 5| is normally restrained against operation by the link 58 of fusible material which has one end engaging the hook 53 while its opposite end is anchored by the pin 59. The link 58 is spaced from the body of the base 59 by the lugs 69 in order to render it more responsive to a temperature rise.

The spring contactor 6! is mounted in the base 59 at 62. It is connected to the contact 57 by the conductor 63. It extends over the lever 5! but is normally spaced therefrom, see Fig. 3. It may be manually forced into operative contact with the lever 5i by the push button 64. This enables a fire alarm to be manually efiected if conditions warrant.

A blaze will fuse the link 58 permitting the spring 54 to swing the lever 5! through its operative position. This momentarily closes the given fire alarm circuit as described.

When the circuit is closed, current flows from the battery 21, through the common line 25, the closed firm alarm switch 49, and over the individual line 2 to the central exchange. Here the current passes through the closed relay switch E5, the wire 24, and energizes the coil 23 to operate the indicator 231:. This gives visual indication of the address of the fire. The current continues through the circuit over the wire 25, energizes the relay coil 26, and flows back to the battery 2?.

Energizing the coil 26 closes the switch 28. This closes the circuit including the battery 29, the switch 28, the wire 3|, the audible and visual signals 32 and 33, and the wire 34 leading back to the battery 29. This calls the telephone operators attention to the fire alarm. The operator then calls the fire station nearest the blaze and rz aotifies the firemen of the address indicated at The closing of the switch 28 also completes a circuit through the wire 36 to fire alarm signals located in the fire houses 3535 and back to the battery 29 through the wire 31. This gives a preliminary signal to the fireman in advance of the call by the telephone operator.

The closing of the switch 28 also supplies current to the motor 38 through the wires 39 and 49. The operation of the motor 38 drives the disk 4| at predetermined speed. When the disk 4| has completed one revolution, the bus contact 42 engages the contacts 43, 44. This closes the circuit from the battery 29 through switch 28, the wires 48, 45, the coil 46, and back to the battery through the wire 41.

Thus energizing the coil 46 opens the switch 28. This discontinues the operation of the signals 32, 33 and the signals in the fire stations 3535. It also cuts ofi the supply of current to the motor 38. The motor 38 has sufficient momentum after the current is cut off to rotate the disk 4! enough to move the bus contact 4! from engagement with one of the contacts 43, 44. This opens the circuit of restoring relay coil 49 so as to preclude its operation at the commencement of the succeeding cycle of operation.

The indicator 23x is manually returned to inoperative position by the telephone operator by any convenient means. This gives the operator unlimited time to call the fire station and to record the address of the fire.

Having described the invention, what is claimed and desired to be secured by Letters Patent is:

1. In combination with a telephone electrical system having a plurality of subscribers stations therein each with a pair of individual telephone wires leading therefrom to a central exchange; a common conductor having a source of current therein and leading to said stations and connected to one of each pair of said individual wires through normally open switches, a plurality of electrically operated indicating means at said exchange; the individual wires which are connected to said common conductor, being separately connected to the opposite end of said conductor through said indicating means; and fire alarm means rendered operative by the flow of current in said common conductor.

2. In combination with a telephone electrical system having a plurality of subscribers stations therein each with a pair of individual telephone Wires leading therefrom to a central exchange; a common conductor connected to one of each pair of said individual wires adjacent said stations through normally open switches; a plurality of electrically operated indicating means at said exchange; the individual wires which are connected to said conductor being separately connected to the opposite end of said common conductor through said indicating means; a source of current and a coil in said common conductor; a fire alarm system having a control relay switch operated by said coil; and means for opening said relay switch after a predetermined period when it is closed by said coil.

3. In combination with a telephone electrical system having a plurality of subscribers stations means for closing said switches operated by a 5 rise in temperature; a common conductor connected to the opposite side of each of said switches and leading to said central exchange; and a plu rality of electrically operated indicating means at said exchange; the individual wires which 10 are connected to said switches being separately connected to the opposite end of said conductor through said indicating means.

ADELARD F. MAR'IEL. 

